I am not a family lawyer but I agree with C. So we were expecting clause 14 to refer to spousal maintenance.
In terms of any loss you have suffered it is probably none as there is very little they can write into a child maintenance clause in a consent order that cannot be undone 12 months later on an application to the CMS. I always found that really weird - that you could agree your consent order and 12 months later undo a bit of it but that seems to be the law.
If you both did not want SM then that's fine but I hope it was explained to you about that. My ex husband wanted SM for life and I wanted zero paid to him for SM and a clean break. So we negotiated and ended up with a larger lump sum pay off for him, no obligations to support children (unless they lived with im) and no SM and a clean break so he cannot come back for more. I think some people go for nominal spousal maintenance fo that if things change later they can go for more. It is a very important question to consider at the time. Sometimes it is best to have it and sometimes not.
On the original question then on its face it says if the CMS orders say £500 a month child maintenance and the clause 14 sum was say £1200 then it seems to be saying you go 1200 less 500 but that does not make sense because both CMS and clause 14 relate to child maintenance. I cannot remember if this order is yet stampded/agreed? If not get it corrected. Also your ex husband would probably want it corrected too as it's unclear.
I thought the CMS assessment totally over took whatever was agreed on child support in the original order (although may be not in cases with high payments for school fees etc like mine). If you could say I am paid £2000 a month child support in the order and then people apply to the CMS and get much less and the result is they still get £2000 a mnoth = so £1500 under order and 500 from CMS then it seems to make a bit of mockery of the right to apply for the CMS to assess child support after 12 months.
If it is the other way round and a low original CM and CMS assess at higher then it does not matter at all as the set off is not going to leave the recipient you any worse off I suppose. Apologies for rambling....
in law if words in a contract do not make sense or are unclear you look to the surrounding circumstances to work out what they mean, emails etc. However for court orders if there is an error you can get them corrected and in fact if both sides realise there is a mistake int here they are usually quick to ask the judge to correct it.